Update login.php
Update login.php

在login界面，如果用户登陆过，就不需要再次输入，直接跳转到用户主页。
windshadowlam/ss-panel,jinaviva/ss-panel,noblocknet/ss-panel,a1ickgu0/ss-panel,Iant20/ss-panel,2645Corp/ss-panel,tbuijibing/ss-panel,SharkIng/ss-panel,Hiyori97/ss-panel,2645Corp/ss-panel,noblocknet/ss-panel,a1ickgu0/ss-panel,tbuijibing/ss-panel,SharkIng/ss-panel,orvice/ss-panel,Hiyori97/ss-panel,a1ickgu0/ss-panel,orvice/ss-panel,Hiyori97/ss-panel,jinaviva/ss-panel,windshadowlam/ss-panel,orvice/ss-panel,SharkIng/ss-panel,noblocknet/ss-panel,Iant20/ss-panel,tbuijibing/ss-panel,2645Corp/ss-panel,windshadowlam/ss-panel,orvice/ss-panel,tbuijibing/ss-panel,jinaviva/ss-panel,Iant20/ss-panel